Seiki Takahashi

55.1: 12.1‐inch a‐Si:H TFT LCD with Embedded Touch Screen Panel

A touch screen panel (TSP) embedded 12.1-inch LCD employing a standard a-Si:H TFT-LCD process has been successfully developed. Compared with conventional touch screen panels, which use additional components to detect touch events, the new TSP exhibits a clearer image and improved touch feeling, as well as enabling the LCD module to provide the sensing data through the driver ICs with an integrated readout function. Our new internal digital switching TSP can be fabricated with low cost because it does not require any additional components compared to a standard a-S:H TFT LCD.

38.1: Embedded Liquid Crystal Capacitive Touch Screen Technology for Large Size LCD Applications

A new embedded touch screen panel (TSP) incorporated with liquid crystal capacitive (LCC) sensors and a-Si:H TFT amplifiers has been developed. The size of sensor pixels and capacitance values have been optimized for improved sensitivity. The readout current from a sensor pixel is converted to readout voltage data, and a digital calibration process is conducted. A sensing voltage larger than 1V is obtained with 50gf finger touch, and a highly sensitive multi-finger touch operation has been demonstrated with aproto-type 16 inch qHD panel.

38.4: Invited Paper: In-Cell Embedded Touch Screen Technology for Large Size LCD Applications

Design guidelines for large size liquid crystal capacitive sensor panels have been studied. Based on a model taking both column spacer and glass deformation into account, reductions of column spacer density or elastic constant are found to be effective for improving cell gap sensitivity to touch force. The structure of a-Si IR sensor incorporating IR light source and IR passing filter has been proposed, and the issues of optical sensor method are confirmed to be solved by simulation and experiment results.

Touch‐screen panel integrated into 12.1‐in. a‐Si:H TFT‐LCD

— A touch-screen-panel (TSP) embedded 12.1-in. LCD employing a standard existing a-Si:H TFT-LCD process has been successfully developed. Compared with conventional external touch-screen panels, which use additional components to detect touch events, the new internal TSP exhibits a clearer image and improved touch feeling, as well as increased sensing speed using discrete sensing lines to enable higher-speed sensing functions including handwriting. The new internal digital switching TSP can be fabricated with low cost because it does not require any additional process steps compared to a standard a-Si:H TFT-LCD.

32.1: Invited Paper: LCD Embedded Hybrid Touch Screen Panel Based on a‐Si:H TFT

A new hybrid-type touch screen panel (TSP) has been developed based on a-Si:H TFT which can detect the change of both CLC and photo-current. This TSP can detect the difference of CLC between touch and no-touch states in unfavorable conditions such as dark ambient light and shadows. The hybrid TSP sensor consists of a detection area which includes one TFT for photo sensing and two TFTs for amplification. Compared to a single internal capacitive TSP or an optical sensing TSP, this new proposed hybrid-type TSP enables larger sensing margin due to embedding of both optical and capacitive sensors.